Here's the question. I have an ~1000sqft garage to heat, so I can work on my bikes and cars over winter. There is 1x30A and 2x20A (240v) circuits on a 100A subpanel. I want to run a ceiling mounted electric shop heater. Thinking of using one of the 20A circuits to do that. OR should I use the 30A circuit and run a larger heater? Never had the luxury of anything more than 15A before.